Method of making turnbuckles.



Patented 0011.5,1909.

E. E. JOHNSON. METHOD OF MAKING TURNBUOKLES.

APPLICATION FILED MAR. 25, 1908.

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EDWARD E. JOHNSON, OF ST. PAUL, MINNESOTA.

METHOD OF MAKING TURNBUCKLES.

Specification of Letters Patent.

Patented Get. 5, 1969.

Application filed. March 25, 1908. Serial No. 423,239.

titni thereof; Fig. 3 a view partly in section anchpartly in side elevation illustrating the, first press operation the tubular blank is subjected to; Fig. 4 a view showing the second and last press operation it is subjected to; and Fig. 5 a detail plan showing the shape of the blank I prefer making the tube out of.

The object of this invention is to provide a simple and inexpensive method of manufacturing rod couplings of the turn-buckle type, that is to say, a tubular coupling such as shown in Figs. 1 and 2 which tube consists of a central enlarged portion polygonal in cross section to adapt it to receive a wrench, the end portions of the tube being reduced in diameter and internally threaded for connection to the externally threaded adjacent ends of the rod.

In carrying out my method I take a tubular blank a, which may be cut from a seamless drawn tube or commercial steel pipe or which may be curled up from a blank such as Z) in Fig. 5, the abutting edges being preferably provided with inter-fitting lugs and recesses 79. This tube is slipped up over a punch carried by a shank c and consisting of a cylindrical upper part (Z, an adjacent polygonal portion 6 and a smaller end-portion f, the portions d and 7 being substantially the same length and the polygonal portion 6 being considerably longer than either (Z or f. The tube fits over the polygonal part and the cylindrical part cl and its other end extends approximately to the end of the narrowed part f. The upper end of the tube abuts solidly against the lower end of the shank c. The former or punch carrying the tube is then forced down into a die 9 shaped interiorly to conform approximately to the narrowed part f and the polygonal part c of the punch or former. This action causes the free lower end of the tube to be squeezed inwardly against the pin f (thus forming the narrowed neck portion at one end of the tube) and the intermediate portion of the tube to be pressed inwardly against the polygonal portion of the punch or former. The former 'is then withdrawn leaving the partly formed tube in the die, the upper unshaped end of thetube projecting above the die. The die is then moved automatically or otherwise under another former it provided with a cylindrical recess and a central depending pin 2' which, when the former is forced down over the end of the tube, squeezes in the upper end thereof and forms the upper narrowed neck portion of the coupling. The coupling is then threaded in the usual way. In this manner a very strong light coupling can be made and these couplings may be turned out in large quantities at a minimum expense. hen the coupling is made up from the blank shown in Fig. 5 it will be observed that the press operations cause the interfitting lugs and recesses to become rigidly interlocked, especially at the angular parts connecting the polygonal part with the narrowed necks.

It will be observed that my method may also be carried out with a tube having a polygonal cross-section; and also that any diameter of neck portions may be obtained by successive reductions and that the same size tubular blank will serve for all sizes of couplings required.

I have found in practice that with the heavier gages of tubular blanks the punch portions 0 and f may be dispensed with, (leaving the punch with only the shank c and cylindrical part (Z), as the heavy walls of the blank support themselves when forced into the die g. I have also found that the pin a may be dispensed with for the same reason. It is also obvious that if advisable the portions of the die 9 which conform to I the punch parts 6 and 7 may be separated and made in two dies instead of one without departing from the invention.

The necking of the ends of the coupling serves two purposes: first to bring them to the tubular form adapted to threading/and, second,to make the tubular end portions smaller than the middle portion so that the tap may clear in threading. The necks can be made cylindrical without reducing their diameter or they may be drawn down smaller as desired. For example, it may be desired to have the end portions fit different sized threaded rods :the top portion of the tubular blank may not then need reducing at all in the die.

It will be observed that I do not weaken the blank by stretching the metal outwardly at any point but on the contrary strengthen the blank throughout by bodily compressing itinWardly, thus placing the entire coupling under radial compression. There Will not even be any stretching or bulging of the blank at the vertical corners of the mandrel e as the distance between these corners and the internal Wall of the die is equal to the thickness of the wall of the blank.

Having thus fully described my invention what I claim as new, and desire to secure by Letters Patent, is

1. The method of manufacturing, turn-' buckle couplings having a polygonal middle portion and cylindrical end portions consisting in reducing in dies by compression of the metal bodily inwardly the ends of a polygonal tube and then threading the interior of the reduced end portions.

2. The method of manufacturing turnbuckle couplings having a polygonal middle portion and cylindrical end portions consisting in reducing the one end portion'and: the middle portion of a tubular blank to polygonal form in dies and then reducing the end portions to the required cylindrical diameter in dies, said reduced end portions belng made by pressing the metal bodily 1nwardly andthen threading the interior of.

compression; the tube being interiorly supported during said operation, then reducing the other end by radial compression, and thenthreading theinterior of the end portions; V 1

4. The inethodnof manufacturing turnbuckle couplings havin'g flnniddle portion" adapted to receivea Wrench and cylindrical end port1o'ns,.consistmg in reducing 1n dies by"compr'ess1on of the metal-bodlly inwardly the ends of the tube and then threading th e.

interior of saidreduced end portions- In testimony Whereot lLhgrennto' aflix my signature in the presence of two Witnesses this 6th day of March 1908.

EDWVARD E. J OHNSON Witnesses:

G. M. An1 nn, E. C. GOODMAN. 

